The first wife of Professor Stephen Hawking has said the Government needs a “big overhaul” of its policy towards disabled people and has also called for a “stronger tax policy” to enable more funding.

Jane Hawking said money from “firms who make millions in this country and yet do not pay any tax” should go towards those who need it.

But speaking at a Motor Neurone Disease Association (MNDA) reception at Buckingham Palace, Ms Hawking said she was not optimistic that anything will change.

She was joined at the event – hosted by the Princess Royal – by Prof Hawking, Benedict Cumberbatch and his pregnant wife Sophie Hunter, Michael Ball, Victoria Wood, Greg Davies, Jon Lee from S Club 7, and the presenters from Good Morning Britain.

Prof Hawking was diagnosed with a rare form of motor neurone disease (MND) in 1964 at the age of 22 and given just a few years to live.

Now aged 73, and despite his illness leaving him almost completely paralysed, he is celebrated as one of the most brilliant scientists of the modern age.

Ms Hawking said: “The Motor Neurone Disease Association is doing very valuable work, and my first husband Stephen Hawking is the patients’ patron, and so we’re here to support him as well as to support the Association.”

Asked if enough was being done to support patients with the disease, and what needs to change, she said: “I think they’re doing very well considering that there’s very little support for disabled people and their families from the Government.

“I think the Government needs to do a big overhaul of its policy towards disabled people, towards people with degenerative illnesses and it needs to provide much better support and it needs to have a system for vetting carers who go into people’s homes.”

Asked if she thought that would change, Ms Hawking, who is played by Felicity Jones in The Theory of Everything, said: “No, not at the moment, but I do think that a stronger tax policy, taxing firms who make millions in this country and yet do not pay any tax… the money should go towards this very particular cause.”

Ms Hawking said she does not think the result of the general election will change anything either.

The Theory of Everything is based on the memoir Travelling to Infinity: My Life with Stephen, which was written by Ms Hawking.

It looks back to their days as Cambridge students in the early 1960s, when the then-cosmology undergraduate was first diagnosed with motor neurone disease, which went on to rob him of most physical movements.

Reflecting on how she has been thrust into the limelight following the success of the film – for which Eddie Redmayne won an Oscar for playing Prof Hawking – she said: “It’s been very exciting and it’s a once in a lifetime opportunity so I think I can cope with it. It has meant that life has been very, very busy, very full, not a moment to spare.”

Asked if she had any concerns about the film being made, she said: “Of course I did, but I would not allow the film to go ahead. Each time Anthony McCarten, the producer, came to see me from 2004 onwards I said no every year. No, no, no.

“Until in 2013 he said well we’ve got an invitation to go to Working Title, the best British film company, so I said right we go. And I was so impressed with the sensitivity that they were bringing to bear on the project that I said yes we’ll go ahead.

“Previously the time wasn’t right for the family, for Stephen, for me, but then the time was right.”

And how did she feel the first time she watched the film? “Overwhelmed. It was beautiful,” she said.

Ms Hawking greeted her ex-husband in the Palace’s white drawing room where the 41 guests, including the Princess Royal, mingled before dinner.

Cumberbatch, who played Prof Hawking in a 2004 BBC drama, went over to the famous scientist and bent down to speak with him, as well as posing for photographs.

The Sherlock star, dressed in a velvet jacket, greeted Victoria Wood with two kisses and chatted with Michael Ball.

He stayed close to the side of new wife Hunter for most of the event and also put his arm around her.

Hunter was wearing a full-length navy gown – complete with patterned top and feather embellishment – which skimmed over her visible baby bump.

Cumberbatch has been a patron of MNDA for 11 years.

He said he first became aware of MND back in 2003 when he played Prof Hawking in the BBC’s Hawking, and as part of his research into “this brilliant man” he worked with the charity which introduced him to two people who had MND at different stages.

“I’m very proud to still be involved – alongside Stephen – with the MND Association today,” he said.